Influence of climate change on flowering phenology of Yoshino cherry at its southern distribution limit

To clarify the influence of climate change on the flowering phenology of Yoshino cherry at its southern distribution limit, we examined the relationship between cold exposure for endodormancy release (chilling requirement) and heat requirement for bud growth on Hachijojima Island, Japan, from 1948 to 2024. Cold exposure and heat requirement had a significant relationship approximated by linear or log-linear functions. In years with less cold exposure, the first flowering dates were much later than normal, in accordance with the higher heat requirement. Our results indicate that the variation in the balance between cold exposure and heat requirement depending on the pattern of annual air temperature change is likely to vary the first flowering date greatly at the distribution limit of Yoshino cherry.